Commutator truing mechanisms



Nov. 17, 1936. w. spGREEN COMMUTATOR TRUING MEC'HANISMS ZO6L398 F` iled Oct. 29, 1934 1NVENT0R #M M BMV/www2 ATTORNEYS Patented Nov. 17, 1936 UNITED STATES PATENT OFFICE 4 Claims.

My invention relates to improvements in commutator truing mechanisms.

'I'he object of my invention is to provide a machine tool having special devices to accomplish 5 the truing and undercutting of commutators, especially such commutators as form the parts of armature assemblies found in the starters and generators of automotive vehicles.

More particularly stated, vit is the object of my invention to provide a machine tool in the general configuration and having some of the general characteristics of a lathe, but provided with work holding chucks and special tools to be used in combination therewith for accomplishing a series of armature truing and conditioning operations.

In the drawing:

Figure 1 is a plan view of my improved commutator truing mechanism, with an armature commutator in position for a truing operation.

Figure 2 is a front elevation of the structure shown in Figure 1.

Figure 3 is a section on line 3 3 of Figure 2, but showing the undercutting device in position for operation.

Figure 4 is a radial section through my improved chuck.

Like parts are identified by the same reference characters throughout the several views.

My improved commutator truing and conditioning mechanism is incorporated in a device which, in its major structural elements, comprises a somewhat conventional lathe frame or bed I0, a tailstock I I longitudinally adjustable along the bed, a headstock I2, and a motor support frame I3 for a motor I4.

The improvements which I have incorporated in the general structure described above are to be found in the chucks I5 and I6 mounted respectively in the tailstock and headstock, and in the structure shown most clearly at the left of Figure 3 and comprising mechanism indicated generally at I1 for undercutting the insulation between commutator bars, as will hereinafter be described. 45 In the use of my improved mechanism, an

armature I8 on its own shaft I9 is mounted between the headstock and tailstock II and I2 forI rotation by a belt 20 which passes over pulley 29 upon motor shaft 2I, and also passes around the body of the armature I8. Belt 20 is tightened by the weight of the motor I4 upon its frame I3, which is in pivotal relation to a slide rod 22 extending along one side of the bed I0.

In the event that the motor I4 is excessively heavy so as to exert too great a tightening eiect upon the belt 20, adjustable stop 23 in threaded engagement with the frame I3 may be adjusted to contact with the bench (not shown) or other support for my mechanism.

Headstocc and talstoclc chucks The tailstock I I and the headstock I2 are pro'- vided with bearing sleeves 24 and 25, respectively, in which chuck tubes 26 are receivable, and each of the chuck tubes is provided at its interior or Work holding end with a radially outwardly extended'ange 2l. There is thus provided within the tubes 26 ample room for the reception of the ends of the armature shaft I9 and the means for adjusting and centering the shaft I9 form the 15 chuck mechanism about to be described.

The iiange 2l upon the tube 26 is radially bored at spaced points 23 about its circumference for the reception of dogs 29, which are of sufficient length to contact on shaft I9 of an armature, and 20 to extend therefrom to a rounded extremity 3!) which may contact the interior face of conically shaped chuck ring 39 which is in threaded engagement at 3| with the exterior of the tubes 26.

Dog springs 32 secured to the ange 2'I inter- 5 mediate the dogs 29 extend arcuately, as shown in Figure 4, through apertures in the outer ends of the dogs 29 and are of such characteristics as to normally thrust the dogs radially outwardly against the interior surface of the chuck ring 36', and it will be apparent from the above description that l have provided in my chuck a rapid action centering or chucking device, since rotal tion of the chuck ring 36 upon the tube 26 will, in the one direction, thrust the dogs inwardly into contact with a shaft I9, or, upon counterrotation of the chuck ring 30', will permit the springs to withdraw the dogs 29 from contact with the shaft, and since the interior surface of the chuck ring 36 is a true cone and the dogs are of equal length and accurately radially positioned, a shaft I6 must necessarily be accurately centered when the dogs are brought into contact with it simultaneously by the thrusting action induced by the crowding of the inner surface of the chuck ring against the outer ends of the dogs.

Tool holder vided with receptor 44 to receive a threaded carriage actuator 45 provided with a crank arm 46, This carriage actuator 45 is in threaded engagement with the tool carriage 43, and rotation of the carriage actuator, which is longitudinally immovable with respect to the receptor 44, results in the adjustment of the tool carriage upon the carriage rails. A tool holder 41 is adjustable by means of a knurled knob 4l with reference to the tool carriage 43 radially of the center of the chuck tubes 26, and a set screw and lever, as shown at 48, may be used to positively position the tool holder when the proper adjustment thereof has been secured. It is thus possible, by means of the tool carriage adjustment and the tool holder adjustment, to position a tool 49 with reference to a commutator 50 or armature i8, so that a truing operation upon the individual commutator bars may be performed while the motor i4 with its pulley 2U' causes the rotation of the armature I8 by means of the belt 2U.

Undercutting mechanism Opposite the tool carriage 43 or rearwardly of the machine, and rearwardly of the armature 5E), I provide a spindle support 6G mounted upon a vertical post iii extending through a bracket 52 receivable upon and capable of sliding upon the bed le, as shown distinctly in Figure 3. The post Si is undercut at 53 to receive the head 54 of an adjusting screw '55 in. threaded engagement with the bracket 62, and since the post 6l is vertically slidable through the bracket 62 the verticaladjustment of the adjusting screw will so position the head 64 thereof within the undercut portion of the post Bl as to positively position the height of the spindle support 6B.

The spindle support B is provided at with a spindle rotatable in the support. This spindle is provided at one end with an undercutting tool 6l and at the other end with a spindle pulley 58. Aiboss 69 on the side of the support Gil provides mounting for a pair of idler pulleys 'iii and lll, so disposed respectively as to receive a belt 'l2 passing to and from a pulley 58, and to and from pulley 23 when the motor is slidably moved with its frame 23 upon rod 22 to dispose the pulley 20 opposite the support Iii?.

The support Sii is rotatable upon the vertical axis of the post 5l which rotates positively therewith, and in its rotative adjustment with the post 6I may be positively positioned by a set screw lf3.

A control handle l5 pivoted at iii upon a pin secured to the bed lli is connected to the bracket `552 by means of a link shown at ll in dotted lines in Figure l, whereby the operator of my improved mechanism may slide the bracket along the bed,

'thus sliding the support @il and the spindle e5 longitudinally of the bed for forcing the undercutting tool longitudinally oi an armature mounted in the chucks above described. When the undercutting tool is not being used the belt l2 may be removed from the pulleys and the spindle may be swung around to the position shown in Figure l, where it may be secured against rotation by the set screw 13.

From the above description it will be apparent that I have provided in one mechanism facilities for rapidly and accurately truing and undercutting an armature commutator. The rapid action of the chucks above described permits the opert^r to quickly center an armature in position for the reception of rotative power from the belt 20 when the motor is positioned upon the rod 22 therefor, and the tool 49 is easily and readily brought into position for a cutting operation to true the commutator as illustrated clearly in Fig. ures 1 and 2.

When a truing Operation has been accomplished the belt 20 may be removed from the pulley 20', and the belt 12 may be extended about the pulley ZES'. The motor may then be moved to position the pulley 20' opposite the support 60and the support 5U may be rotatably moved to the posii tion shown in Figure 3 to dispose the undercutting tool 6l in a groove between the commutator bars of the commutator. The belt 12 may then be laced over the pulleys 1U and 'H and over the pulley G8 on the spindle G6 to rotate the undercutting tool, and the control handle 15 may be oscillated to cause reciprocation of the support and its associated mechanism within the limited range necessary for the undercutting operation.

claim:

1. In a device of the character described a bed and a headstock and tailstock spaced thereon for reception of work to be revolved, a motor supported from the bed and adjustable longitudinally thereof, a tool holding carriage supported from the headstock and a, tool holding spindle supported from the bed and swingable to and from working position, the'spindle being provided with power connections engageable with the motor when the motor is adjusted along the bed to a position of alignment therewith.

2. In a device of the. character described a bed and a headstock and tailstock spaced thereon for reception of work to be revolved, a tool holding carriage adjustably supported `from the headstock and provided with a tool for operation upon the work in the rotation thereof, and a tool holding spindle supported from the bed and swingably movable to and from a position for operation upon the work when the workvis stationary in the stocks and a motor adjustably mounted from the bed and provi-ded with power connections alternatively usable in various adjustments of the motor, whereby to rotate the work or operate the tool in the spindle.

3. n a device of the character described a bed and a headstock and tailstock spaced thereon for reception of work to be. revolved, a tool holding carriage adjustably supported from the headstock and provided with a tool for operation upon the work in the rotation thereof, a tool holding spindle supported from the bed and swingably movable to and from a position for operation upon the work when the work is stationary in the stocks, power connections alternatively connectible to the work or to said spindle, said power connections including a motor device mounted for adjustment longitudinally of the bed and provided with a pulley to be thereby positioned operatively opposite the spindle or the work to be revolved.

4. An armature commutator truing device including chucks for reception of the armature, a motor provided with a pulley and belt to engage the armature whereby to rotate it, and a tool spindle support provided with a pulley and tool holding spindle adjustable whereby to dispose the pulley in belt alignment with the pulley on the motor.

WILLIAM S. GREEN, 

